There are many different types of traffic channelizer devices for directing and channeling traffic flows. One type that is widely used comprises a hollow drum made of a relatively lightweight plastic material that will cause little or no damage to a vehicle if the vehicle should accidentally strike the drum.
Because such hollow plastic drums are relatively light in weight, some type of ballast is needed to prevent the drums from being inadvertently blown over or moved about by the wind and/or air blasts produced by passing vehicles. One common form of ballast comprises one or more rubber-like collars that may be placed over the drums for exteriorly ballasting the drums. Such collars may be molded out of a suitable rubber-like material or comprise a relatively rigid bead portion and a relatively non-rigid integral side wall portion of a recycled tire such as a truck tire.
An example of one such drum and ballast system is disclosed in U.S. Pat. No. 5,234,280 assigned to the same assignee as the present application, the entire disclosure of which is incorporated herein by reference. The drum disclosed in this patent includes a radially outwardly and axially downwardly tapering skirt portion adjacent a bottom edge of the drum for resisting pull out of the drum from the ballasting collar so the drum cannot be blown or sucked out of the ballasting collar by the wind or passing vehicles. Also, the ballasting collar grips the road over a relatively large surface area to resisting tipping of the drum and eliminate “walking” of the drum on the ground which is common in plastic drums. However, the drum is deformable upon impact by a vehicle to cause the drum to collapse sufficiently to permit the skirt portion of the drum to pass through the ballasting collar to dislodge the drum from the collar leaving the collar behind.
There is a tendency for the drum to rotate relative to the ballasting collar especially when a warning light or other safety device is mounted off center on the top of the drum. This occurs from the wind and vacuum created by passing vehicles exerting a rotational force on the drum, and has the disadvantage that the drum may rotate such that only a portion of the warning light or other safety device is visible to oncoming traffic.
One known way of preventing drum rotation relative to the ballasting collar is to attach a friction pad to the lower outside surface of the drum for contact by the inner diameter of the collar when the collar is inserted over the drum. If the friction pads are cut from recycled tire tread pieces that vary too much in thickness or the ballasting collar is cut from recycled tires having inner diameters that vary slightly, the ballasting collar may either not adequately engage the friction pad to prevent relative rotation or the friction pad may interfere with the proper placement of the ballasting collar around the drum.
Another known way of preventing drum rotation relative to the ballasting collar is to attach two molded ribs to the bottom outside surface of the drum for contact with the inner diameter of the ballasting collar. A problem with using such molded ribs is that if the inner diameter of the ballasting collar is too great, the collar may not adequately contact the molded ribs to prevent rotation. Conversely, if the inner diameter of the ballasting collar is too small, the molded ribs may interfere with the proper placement of the ballasting collar over the drum. Moreover, the molded ribs add to the overall cost of the drums.
Another common form of ballast comprises a molded rubber base that is held in place inside the bottom of the drum by a continuous inturned lip on the bottom of the drum. One problem with this is that there is a tendency for the internal base to prematurely separate from the drum when the drum is tipped at an angle and dragged along the ground from one location to another. Also, repeated vehicle impacts and/or repeated dragging of the drum bottom along the ground may cause the inturned lip to become sufficiently distorted or worn that it is no longer effective in retaining the internal base inside the bottom of the drum.
The drums are typically stepped radially inwardly at discrete intervals along their length from the bottom toward the top to facilitate stacking of the drums during shipment and storage and to provide a plurality of axially spaced surfaces for applying one or more bands of reflective sheeting to the drums. However, care must be taken to prevent overstacking and lock up of the drums when stacked together. Otherwise it may be difficult to pull the stacked drums apart. Also it is desirable to protect the bands of reflective sheeting against damage during stacking.
It is also generally known to attach portable sign assemblies to traffic channelizer drums to provide a Type I or Type II directional barricade for redirecting traffic. Such portable sign assemblies should be easily attachable and removable from the drums to allow the portable sign assembles to be removed to permit stacking of the drums during transportation and storage.
One of the problems of making the portable sign assemblies easily removable from the drums is that the wind and vacuum created by passing vehicles may cause the portable sign assemblies to rotate relative to the drums such that only a portion of the portable sign assemblies may be visible to oncoming traffic. Also, the portable sign assemblies may slide up on the drums, causing the portable sign assemblies to prematurely become dislodged from the drums.
A need thus exists for improved traffic channelizer devices that eliminate one or more of the drawbacks of previous traffic channelizer devices outlined above.